Limited data are available on the slowing of myopia progression, its eventual stabilization, and related risk factors. Juvenile-onset myopia typically is thought to stop progressing at 15 -16 years of age, yet data from adults show that progression can sometimes continue at least through the 20's. Analysis of refraction data from subjects enrolled in the Collaborative Observational Study of Myopia in COMET Children (COSMICC) shows that currently, at an average age of 17 years, myopia has stopped progressing in only 42% of the cohort. This group of ethnically diverse myopic subjects has 7-8 years of standardized, reliable measurements of refractive error and ocular components, with outstanding retention of 93%. Thus, this cohort provides a unique opportunity to characterize progression and stabilization of myopia and to learn how they are influenced by intrinsic (e.g., age, ethnicity) and environmental factors (e.g., type of lens worn, near work and outdoor activities) identified from this study and from the literature. With the higher amounts of myopia found in some of our subjects (22% with >6.0 D), we also plan to investigate the association of increased progression and axial elongation with intraocular pressure (IOP), central corneal thickness (CCT), and macular thickness. These results will help to identify individuals with increased risk of myopia-related pathology as well as help guide the selection and timing of interventions, including vision correction surgery. By studying this cohort for an additional 5 years, this application seeks to accomplish the following aims. Aim 1: To use the Gompertz and other functions to characterize the course of myopia in the 58% of the COSMICC cohort with progressing myopia and to develop predictive models based on previously identified, intrinsic risk factors (age, ethnicity, and parental myopia). Aim 2: To test hypotheses related to environmental risk factors (e.g., type of lens worn, near work and outdoor activities) for myopia progression and stabilization in this well-characterized cohort of myopes. Aim 3: To test hypotheses related to the association of IOP, CCT, and macular thickness with changes in axial elongation and myopia progression in COSMICC subjects. This application is for the COSMICC2 Study Chair. Separate applications have been submitted by the 4 clinical centers and the Coodinating Center.